A Twist In The Knickers
by MizJoely
Summary: Sherlock needs Molly's unmentionables for an experiment...but is that all it is?
1. For Science

_Co-written by the incomparable lilsherlockian1975. This story is complete (huzzah!) and has 3 chapters and we hope you enjoy the cracky smut you're about to read._

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"Molly! Take off your knickers!"

"What, now? Why?"

Sherlock, who had burst into the path lab as if his own knickers were on fire, screeched to a halt in front of her. "Er, for...science?" he half-said, half-asked, looking very shifty as he did so.

Molly gave him a narrow stare. "Do I have to make you pee in a cup?"

He shook his head, looking offended at the very thought. "No, course not! I have no interest in getting slapped by you again unless it's recreationally!"

"And don't you forget it!" she snapped, then did a quick double-take. "Wait, did you say _recreationally_?"

He glanced at his watch. "Get on with it, Molly!"

"What could you possibly do, _scientifically_ , with my knickers?" Molly asked as she crossed her arms over her chest.

He huffed, hands on his hips, and explained, "I won't know that until you take them off, now will I?" He motioned to her hips. "Let's go. Haven't got all day."

" _Sherlock_..." She walked up to him and looked him over carefully. Slowly reaching up, she dug her fingers into his hair.

He swallowed. "M-Molly..." Closing his eyes as her fingers moved across his scalp, he tried to collect himself.

"Nope!" she said, then her hands were gone.

He opened his eyes to see her looking at him questioningly.

"Nothing! Not a single bump. Okay, I give up! What the hell's wrong with you?"

He drew himself up to his fullest, most intimidating height and stared down his nose at her, not realizing how much he resembled his elder brother as he did so. "There is nothing wrong with me, Molly Hooper, that the use of your knickers...for science...can't fix. You're wearing a skirt today, with thigh-high stockings underneath, so it shouldn't take more than a tick for you to remove the lacy black scrap you're wearing." He held out his hand expectantly.

"How do you know which ones I'm...never mind," Molly interrupted herself. She was actually getting interested in seeing just what Sherlock would do with the, quote 'lacy black scrap' she had on, and so she slowly, deliberately slid her hands down her thighs to the hem of her skirt, sliding it up just enough to show the tops of her thigh-highs.

Sherlock, she noted, gave an audible gulp as she did so and took a single step backwards. What, did he not expect her to rise to the challenge he'd just presented?

A wiggle and a couple of skips (to clear the 'scrap' past her kitten heels) later Molly was holding up her sexiest pair of black lace knickers. "Here you go." When Sherlock didn't move she grabbed his right wrist and placed them in his hand. "Anything else?" she asked with a smirk.

"Ah..." Sherlock stared down at his hands as if he were waiting for them to do a trick. Finally he looked up. "Not at the moment, Dr. Hooper," he said as he stuffed the garment into his coat pocket. He then turned on his heels and marched out of the lab... _with her knickers_.

Molly was too stunned to say a word in protest. She just shook her head and tried to remember if she had a spare pair in her locker. _Oh, crap.._.

Her shift ended four hours later. She was pretty proud of herself for not panicking and begging off half the day. As a matter of fact, there was something sexy about walking around the hospital _pantless_. Though she thought it might have been different if a body had come in. Of course the end of her shift brought her to a bit of dilemma: should she go retrieve them or count them as lost?

Deciding she just didn't have the energy to further confront - or was it tease? - Sherlock, Molly opted to just head home. However, she didn't quite have the nerve to brave the Tube knickerless, so she sprung for a cab instead, trying not to fidget the entire way. Going knickerless at work while either standing at an autopsy or sitting behind a desk with a nice long lab coat on was one thing; riding in a cab with only her above-the-knee skirt and colorful blouse was another!

It seemed to take twice as long to get home by cab, but finally she was safely inside her building. Again she was faced with a choice: take the stairs as usual or use the lift? She only lived two flights up, but the thought of someone possibly coming up the stairs behind her and accidentally getting a look at her arse and lady bits decided her against the cardio-friendly option.

However, as soon as the lift doors opened she let out a smothered curse: there, leaning against the back wall and smirking was Sherlock.

"Why are you in my lift?" Molly asked, scowling as she stepped in.

As soon as the doors closed, Sherlock leaned forward, closing the distance between them. He was so close, as a matter of fact, that she wondered for a split second if he was going to kiss her...or something. But instead he reached just past her elbow and pushed a button on the control panel. She missed which one but since the lift didn't start to move upward she assumed he'd hit the emergency stop button.

"I just had to pick something up," he explained.

"Pick something up? From where, my flat?"

"From your bedroom, more specifically."

"WHAT?"

"Yes. I needed another sample," he said casually.

Molly studied him for a few seconds, then it hit her. "Turn out your pockets!"

"No."

"What do you mean, no?" She stepped toward him. "How many did you take?"

"I needed a pair of cotton ones. The lace..." he trailed off, with a satisfied smirk on his lips.

"You destroyed them, didn't you?"

Suddenly he was advancing on her and she found herself backed up against the doors. "All's fair in love and war...and _science_ ," he purred.

"What in God's name are you doing with them?"

He brushed her hair over her shoulder and leant forward; his mouth couldn't have been more than an inch from her ear. "Testing tensile strength and... _breathability_ , Dr. Hooper." His voice had never sounded so deep. "Surely you want to do your part for the cause."

It took Molly a moment or two to collect herself. Then she felt his hand move to her hip and squeeze. _Well, that doesn't help._ Her breathing became heavier and she suddenly missed her knickers... desperately.

"Did you enjoy the rest of your workday? Anything interesting happen?" he asked as he moved her slightly away from the doors, removing his hand as soon as he'd done so.

"No, why would it?"

"My day was _fascinating_."

There was a loud beep, then the doors engaged, opening up next to her.

"Have a pleasant evening, Molly." And with a kiss to her cheek, he was gone.

Molly was so caught up in wondering what the hell he meant by tensile strength and breathability - not to mention recovering from the intensity of their odd interaction - that she almost forgot to exit the lift when it arrived on her floor. Since she had no recollection of pressing the button, she could only presume Sherlock had done it for her before skipping off with his ill-gotten gains. Damn, she should have tried to steal them back, but he'd got her all discombobulated what with that deep, sexy voice of his purring in her ear. She rubbed her thighs together and shivered a bit as she entered her flat.

Her plans to go straight to her bedroom and relieve some of the tension Sherlock had stirred up was thwarted by Toby, who nearly tripped her as soon as she entered the flat. His loud, demanding meows soon gave way to appreciative purrs as she opened the tin of cat food and placed it in his dish. "Wish it was that easy with Sherlock," she muttered, tugging her hair free of its colorful elastic.


	2. Experiment in Progress

_A/N: Wow, thanks everyone for your wonderful reviews! Here is part 2, and part 3 will likely be up tomorrow. Enjoy the smutty goodness!_

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Sherlock rode back to Baker Street, his prize in his pocket and a shit-eating grin on his face. "Your move, Molly Hooper," he whispered to no one in particular. _Should I have stayed?_ he wondered. He'd flirted (or he thought he had); he'd stolen her undergarments and had left her something in return. _No, I made the right move. Now she has to come to me… if she dares_.

He expected her to show up at his flat within the hour either angry or aroused. But three hours and two experiments later, no Molly! (She'd get no use out of those cotton knickers now. Her own fault, if she'd shown up when he had expected, they might have been salvageable.) Looking down at the destroyed fabric, he sighed and decided to call it a night. That's when he heard it…

" _William Sherlock Scott Holmes!_ "

He smiled and removed his safety goggles, carefully setting aside the shredded remains of Molly's most boring pair of white cotton knickers. The slam of the front door, the pounding of feet up the stairs...later than he'd expected, but here she was at last.

He turned and carefully placed his hands behind his back, positioning himself so that he was facing the door to his flat, which had been deliberately left partially open. He was wearing his royal blue dressing-gown over his clothes; he'd unbuttoned his aubergine button-down an extra button; his trousers were bespoke and therefore required no pesky belt; and his feet were bare.

He was ready for her.

What he was _not_ ready, for however, was the way she she physically flung his cheeky little hint of a gift at her. "You git!" she screeched as he ducked the flying, penis-shaped ice lollies. At least she'd left them in their wrappers! "What the fuck, Sherlock! Yes, I get it, I'm alone, no fiance, no one to have lots of sex with, it'll just be me and my own fingers for the rest of my life, but this...this is just _cruel_!"

Shit. He'd bolloxed it all up, hadn't he. Shit, shit, shit. "No, Molly, it's not-"

"Not funny? You're bloody well right it's not funny!" Still fuming, she advanced on him, hands balled into fists by her sides, not even slowing when she squished one of the paper-wrapped lollies under her foot.

He snuck a glance downward - cherry, so at least it wouldn't leave too visible a stain on the carpet - then quickly back up to meet her stormy gaze. Raising his hands in a placating gesture, he said, "No, it's not. Nor was it meant to be. I wasn't making fun of you or playing a joke, I promise!"

"Then what the hell _were_ you doing?" she demanded, but at least she'd lowered her voice a bit. To a rather sexy growl, hmm, must find a way to get her to say his name like that...focus!

"Dropping a hint," he replied, deciding on the spot that not only was honesty the policy, but in this case it might also save a life. Namely, his.

His answer brought her up short, both literally and figuratively. He watched her brow scrunch in confusion as she ceased her advance. "A hint about what? My frigid love life?" she asked, but he could both see and hear her uncertainty. Good, good; he much prefered being the one to put people on the back foot.

He shook his head. "Nope."

Molly's face morphed from confusion to realisation to…

 _Ah, that's more like it,_ he thought as he watched arousal wash over her features for a split second before curiosity lit her eyes.

"You're hinting that…" she gestured between the two of them.

"Yep," he said with a grin that he hoped relayed his meaning.

"So all this: the knickers, the frozen penises? You were _dropping hints_ that we should..."

"And flirting, don't forget the flirting!" he interrupted.

"Ah, yes, the lift." She looked him up and down then started walking toward him again. Once she well within his personal space she placed her hands on his chest and pushed him backward. He stumbled at first, slipping on a melting ice lolly, but soon found himself backed up against the desk. She then leaned into him and rose up on her tiptoes bringing her lips as close to his ear as possible and said, "You. Are. Bluffing, Sherlock."

 _Dammit!_ How could she think he was bluffing when he was sporting nearly a full salute already! "Molly, I assure you that I am NOT bluffing."

"Prove it!"

Like a striking cobra he turned his head and hauled her into his arms. His mouth crashed over hers and he thought he heard a muffled squeak of surprise before her tongue became far too busy wrestling with his to form words. In fact, for the next several minutes the only sounds to be heard were those of two pair of lips smacking and some very approving hums coming from two throats.

When they finally pulled apart, gasping for breath and hair and clothes more than slightly disheveled, his half-mast was at full attention and then some. If Molly were wearing something other than one of her atrocious knit jumpers, he judged he'd be able to see her nipples poking through the fabric. His fingers twitched at the mental visual, and he would have dived right in if Molly hadn't taken a sudden step back, watching him through wide - perilously close to wild - eyes. "What was that?" she demanded.

He stepped forward; she stepped back again and he stopped. "Proving it?" he half-asked.

She gave a small nod. "Right, OK, not bluffing," she said. "Sooo...um, what…"

"Sex, Molly," he said impatiently, holding himself back with inhuman effort. "Sex. With you. Us. Judging by what you've told me in the past, surely it doesn't alarm you?" He raised a sardonic eyebrow and tilted his head.

Her brow lowered and lips thinned; that was all the warning he received before she launched herself at him, throwing her arms around his neck and sending them both crashing to the floor. He came perilously close to smashing his head on the fireplace; she got one leg trapped under his chair as she tried to kick off her ballet flats, and then they were far too busy removing one another's clothing to care about anything else.

 **SMSMSMSMSMSM**

It was insanity! It was utterly and completely insane! They should stop and talk (while putting a respectable distance between one another). They should sit down with tea and some nice chocolate biscuits and talk about what the hell was going on.

Sherlock pulled back to look in her eyes. "You're having second thoughts."

 _This is where I should stop things._ Just a quick chat about what the hell was going on. Or… _Oh, sod it! This is happening!_ She shook her head and reached down to grip his erection through the only bit of clothing he had left on the lower half of his body, his pretty royal blue boxers.

"Thank- oh fuck!" he mumbled and shouted at the same time.

Molly was only wearing her bra and knickers, having lost her jumper and jeans during those first few moments of rolling around on the floor. Sherlock wasn't nearly naked enough for her liking. Sitting up, she took hold of his shirt and ripped it open. Buttons flew wildly across his sitting room floor.

He stared at her, astonished. "This is an expensive shirt, Molly!"

"You've ruined two pairs of my favourite knickers," she countered with a smirk.

"And I plan on ruining one more..." He gently pushed her to the floor. "At least."

Pinning her hands above her head with one of his, he closed the distance between them, capturing her lips and blowing her mind. _Good God! Where did he learn to kiss like this?_ Breaking away from her lips, he nipped and licked across her jaw, down her neck to her sternum then buried his face between her breasts.

"Mmm, gonna want one of your bras to work with, Miss Hooper," he mumbled into her skin. "This one will do nicely."

Molly giggled as the words vibrated her chest. "Can't you just go buy underthings to test on, Sherlock?"

Looking up with a smirk, he said, "Now where's the fun in that?" Then he shoved the cups low and latched onto a nipple, drawing her into his mouth. He kissed his way down her body once he'd seemed to get his fill of her breasts, until he reached her knickers. "What are we calling these?" he said as he traced the seam of her sex through the material.

She leaned up on her elbow so she could look him in the eye. "They're pants, Sherlock."

"I don't think I've ever seen any like this before." He lowered himself until he was no more than an inch away from the soaked fabric. "They certainly weren't in your drawer earlier," he said then planted a kiss on her cotton covered lips.

Molly whined and bucked her hips. "Th-they were in the dryer, you missed them." If he didn't stop teasing and talking about her damn intimates she was going to toss him on his back and impale herself on that lovely erection he was sporting.

Running a finger across the gusset, he said, "Barely covers anything at all, Miss Hooper. You are full of surprises."

"They're called b-boy-boyshorts." He continued teasing her through her underwear. "Get on with it, will you? Just take them off and do...something!"

"I _don't_ think I will," he said, causing Molly to fall back and expel a deep breath. "I think I'll leave them on...for now." He pushed her knees up to her chest. "Hold on, Molly."

 _Hold on to what?_ She grabbed her legs right behind her knees just as Sherlock blew across the wet fabric covering her pussy. "Holy fuck!" she whispered. She heard a dark chuckle then felt him licking her...through her pants! Molly tried to say something- beg him to let her come- but nothing came out. Suddenly he found her clit and sucked it into his mouth. The combination of his lips and the cotton moving over her hard little nub brought her right to the edge very quickly.

"Shit yes!" she shouted as her orgasm started to build. Holding the backs of her legs so tightly she was sure to leave marks, she looked down to see Sherlock watching her intently. Then she was gone. She knew she was shouting something - his name, praise for a job well done or possibly calling out to any deity who would listen - but she couldn't think about that moment, she was too busy floating away. His hands on her thighs were the only thing keeping her anchored to the floor.

"These knickers are completely ruined. This time I blame you, Molly. Just look at what you've done…"

But Molly didn't care about her damn knickers. She sat up and pushed Sherlock flat on his back. He looked faintly alarmed at first, but his expression took on a decidedly wolfish cast as she straddled him, her knees on either side of his hips and her hands flat on his chest. "Time for a different experiment," she said as she ground her core against him.

"Wh-what kind of experiment?" he gasped, holding her by the hips.

She bent low, brushing his ear with her lips as she whispered, "Seeing how long it takes for me to make you scream my name."


	3. Hypothesis Proven

_A/N: Thank you everyone for your wonderful comments on this smutty saga. Lilsherlockian1975 and I appreciate every one of our readers, trust me! Enjoy the conclusion of our NSFW extravaganza!_

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 _Bloody hell._ He knew was in trouble but the knowledge only seemed to, somehow, make him harder. Molly leaned up and, reaching behind her back, unhooked her bra, tossing it to the side. Grinding the wet gusset of her 'boyshorts' against his tented boxer, she palmed both of her breasts at once, throwing her head back and moaning...sinfully.

Helpless to do much of anything other than observe, at least for the moment, Sherlock took her in as she writhed against him, pinching and pulling at her nipples. It was hands down the sexiest thing he'd ever seen. He knew he should attempt to regain control since the recently sated Molly had decided to tease him to the point of pain (or premature ejeculation if she was extremely careful). His brain, however, was having a hard time compensating for the redistribution of blood; most of it seemed to be located in his cock. The sensation of her centre grinding against his straining, still covered, erection was pleasant in the extreme, but frustrating at the same time. For a moment he wondered if it might just burst through on its own accord, demolishing her sad excuse of an undergarment in the process.

Suddenly that brain he was so proud of finally kicked back in, or perhaps it was purely instinctual. At that moment he couldn't actually care less. He needed to be inside her, and for the first time in his life he wasn't above begging.

"God, Molly, please!" he gasped, digging his fingers into her hips.

She sat up, ending the delicious friction but giving him a chance to regroup, and opened her eyes. They were heavily lidded and dark with arousal as she focused her attention on removing his pants. With a quick tug he was finally free. Wrapping her hand around his shaft, Molly stroked him once, twice, then a third time.

He was about to embarrass himself. "Molly…" he growled.

With an infuriating smirk, she pulled her knickers to the side with one hand as she positioned his cock with the other. "Is this what you want, Sherlock?"

Unable to answer, Sherlock thrust upwards, filling her in one smooth motion.

SMSMSMSMSMSM

 _Oh Christ that feels good,_ was Molly's first thought. Her second thought was something along the lines of 'hngghghhhh' and her third thought wasn't any more articulate but involved a lot of internal swearing as Sherlock began moving beneath her. She leaned forward, planting her hands on his chest and matching his movements, feeling the glorious friction of their joined bodies. He pulled one hand from her hip, groping blindly for her hair, tugging it free of the elastic.

Molly leaned down a bit more in order to drag the ends of her hair across his exposed flesh. The loud moan this elicited brought a satisfied curl to her lips. "Hmm, looks like I'm not the only one with a hair fetish," she purred, altering her position so her hair brushed his nipples.

Sherlock, it seemed, was in no mood to take her teasing lying down; he surged upwards, wrapping his arms around her body and rolling them so that she was deliciously trapped beneath his lean, supple form. "Molly Hooper," he growled as he thrust his hips against hers, "you and your hair have been driving me absolutely mental since day one. Forgive me," he thrusts against her even harder, "if I am done with being teased by either of you for a while."

Molly had absolutely no objections to either his words or his movements. She twined her arms around his neck, linking her hands at the wrist and pulled him down for a long, heated kiss. Then she lifted her legs, wrapping them around his narrow hips and dug her heels into his sweet little arse. "Harder," she begged, nipping at his ear. "Faster. God, Sherlock, please!"

He obliged her immediately, pistoning his hips, grunting in time with every thrust. The feel of his chest against her nipples only added to her spiraling pleasure. "Ohhhh," she moaned, her breaths coming in harsh pants, sweat coating her body. "Sherlock, I'm gonna, I'm….AHHHHHHHHH!"

She screamed out her completion into the hot divot between shoulder and neck, biting down hard as her orgasm shuddered through her body.

Seconds later, while she was still drifting down from her high, she felt Sherlock's entire body go taut as a bowstring, heard him groaning her name between swear words, felt the hot gush of his cum filling her...and gasped as the feel and scent and sound of his climax seemed to fuel another one for her. "Shiiittttt," she gasped, having never experienced such a biological miracle before. _I guess Meena wasn't lying after all_ , was her delirious, near-ecstatic first thought. _Have to remember to call her and apologize._

Then Sherlock was kissing her, holding her close as he rolled them over so she was sprawled across his hot, delicious body, and all thoughts of anyone else - even her best friend from uni - went flying out of her mind.

SMSMSMSMSMSM

Sherlock released a deep, contented sigh. _Perfection_. Just as he'd expected. No, better actually. Even his exceptional mind hadn't been able to imagine that sex with Molly would have been this good. This…this… _oh, fuck it! I can't even put it to words right now._

Molly shifted and started to get up but he stopped her, gripping her shoulders tightly. "Where do you think you're going?" he demanded.

Looking up, she said, "Ah, well… I thought..."

"We aren't finished, Molly."

"Sherlock…"

"This was just the first in a whole series of experiments that I have planned," he said with a smirk.

Molly sighed ash she sat up, grabbing his buttonless shirt and covering her chest. "I'm not an experiment, Sherlock." She refused to meet his eyes.

Her words made his chest constrict as he realised his mistake. "Look at me, Molly." Raising her eyes, she looked at him, insecurity and fear was evident. Sherlock took her face in his hands, rubbing her cheeks gently with his thumbs. "Of course you're not. You are _so_ much more."

"How much?"

He kissed her cheek. "Hmm? Well, how attached are you to your flat?" he asked, then kissed her other cheek.

"Pretty attached," she answered. "Have you _seen_ my kitchen?"

"You don't cook, Molly." He placed a series of kisses down her throat. "You can make tea just as easily here."

"Ahh, good... ahh…point."

Sherlock smiled as he pulled his shirt away and laid her back onto the floor as he continued his kisses down her chest.

"So, you're asking me to move in just to do more experiments?" Molly asked as she threaded her fingers through his hair.

He looked up. "Of course not! I'm asking you to move in because I'm in love with you, you silly woman! Now, stop distracting me, I'm trying to do science."

"On one condition."

He paused in the act of leaning forward to kiss her again. "Which is?"

She met his gaze with a wicked smile. "Lend me a pair of your knickers?"


End file.
